package/swupdate: bump to version 2021.04

package/swupdate: bump to version 2021.04

Add new optional dependencies.

Drop patches that are now upstream.

License update details

LICENSES/BSD-1-Clause.txt:
https://github.com/sbabic/swupdate/commit/e419b06b497ee627b05cbc33d4b4df064137d0de

LICENSES/BSD-2-Clause.txt:
https://github.com/sbabic/swupdate/commit/32c1f98eaca69e362be074197f84a59d994c0876

LICENSES/BSD-3-Clause.txt:
https://github.com/sbabic/swupdate/commit/32c1f98eaca69e362be074197f84a59d994c0876

LICENSES/CC0-1.0.txt:
https://github.com/sbabic/swupdate/commit/7c3630f572e6d00d7c51b7c4925494c7a822aef9

LICENSES/CC-BY-ND-4.0.txt:
https://github.com/sbabic/swupdate/commit/b66db00c56f9960e9983e1a6d36eef4f151124a8

LICENSES/GPL-2.0-only.txt:
https://github.com/sbabic/swupdate/commit/af2cc98b44cc6a066c0be4511406294e9113e4b1

LICENSES/GPL-2.0-or-later.txt:
https://github.com/sbabic/swupdate/commit/11af069b85475f5bcaa094261259a6b40e363986

LICENSES/ISC.txt:
https://github.com/sbabic/swupdate/commit/6500f1e89a097bd12d0ac42f6c7cc7ee284a6e17

LICENSES/LGPL-2.1-or-later.txt:
https://github.com/sbabic/swupdate/commit/4ef88a9df89ddd445597ef49309563d29cb72607

LICENSES/LicenseRef-OpenSSL-Exception.txt:
https://github.com/sbabic/swupdate/commit/2f513d117c5948ca9d950bbb82f05e8e38cbab50

LICENSES/MIT.txt:
https://github.com/sbabic/swupdate/commit/c1bad02cb93ff9bc616029cd27318134d36cfacb

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>